How much does it rain in the UK?

Where gets the most rain?

As can be seen in the map below, the wettest parts of the UK are concentrated in mountainous regions with observation sites in Snowdonia, the Lake District and the Scottish Highlands all receiving more than 4 metres of rainfall in a year.

Other rainy parts of the UK include:

  • North west England - especially the Lake District in Cumbria and western facing slopes of the Pennines.
  • Western and central Wales - particularly the mountainous Snowdonia region in the north.
  • South west England - mainly the higher elevation areas of Dartmoor, Exmoor and Bodmin moor.
  • Parts of Northern Ireland.

These areas all have common characteristics, given their high elevations (or even mountainous status) and their northern or western locations in the UK.

Area Rainfall (mm)
1 Argyllshire 2274.9
2 Dunbartonshire 2066.5
3 Inverness 2034.8
4 Merionethshire 1914.0
5 Ross and Cromarty 1858.1
6 Carnarvonshire 1809.7
7 Buteshire 1771.2
8 Kirkcudbrightshire 1696.7
9 Westmorland 1652.6
10 Brecknockshire 1643.7

Why do some places get more rain than others?

The map shows a clear divide between the north-west and south-east of the UK. The prevailing warm moist westerly winds mean that the west of the UK is more likely to receive rainfall from Atlantic weather systems - in the form of frontal rainfall. These weather systems usually move from west to east across the UK and as they do so the amount of rainfall they deposit reduces.

This is because the mountains of the northern and western UK force the prevailing westerly winds to rise, which cools the air and consequently enhances the formation of cloud and rain in these locations (this is known as orographic enhancement). Of course, frontal and orographic rainfall are not the only rainfall mechanisms, but they are the most common in the UK.